With shoulder straps

Advantages

No need for for adhesive tapes.

You can wear them without a ( pocket) bra. (But a bra will support, lift and shape them like a bra does for real breasts. The result will be a very realistic and comfortable feeling and stunning looks.)

No gaping when you lean forward.

Straps allow height adjustment for a perfect fit.

Drawbacks

More difficult to put on than separate breast forms.

Without shoulder straps

Advantages

Easy to put on.

Drawbacks

You can not wear them without a bra.

1000 grams are so heavy you may need a pocket bra to keep them in place. Because breast forms are heavy and not attached to your body like real breasts, they hang in a bra like dead weight. They will pull a normal bra downwards, fall sideways or slip out at the bottom.

Teardrop shape

Advantages

Drawbacks

Asymmetrical shape

Advantages

These are the only forms that look and feel real. Tapered edges blend to the body. (Real women have breast tissue that extends to the side and under their arms. Their breasts are not interchangeable from right to left.)

Drawbacks

Hollow back

Advantages

Suitable if you have small breasts or large pectoral muscles. The concave back will wrap around your flesh, not hobble on your chest like a see-saw.

Drawbacks

Solid back

Advantages

Suitable if you are very flat chested.

Drawbacks

Separate forms

Advantages

Suitable if you have a big chest. You can position them at whatever width suits you best.

Drawbacks

Conjoined on a plate

Advantages

It is possible to get a reasonably looking cleavage.

It is possible to pose topless with a reasonably realistic looking appearance.